Particulate Air Pollution Strongly Linked With Increased Diabetes Prevalence in US Study

A new study published in Diabetes Care finds that there is a strong link between particulate air pollution and the rising prevalence of adult diabetes in the United States. Pollution was found to be a serious risk factor even after other risk factors, such as obesity and ethnicity, were adjusted for. What's more, the relationship between pollution and diabetes occurs at levels below current EPA limits.The report opens, commenting on the connection between particulate air pollution and diabetes:

Environmental pollution, especially particulate matter between 0.1 and 2.5 micrometers in size (PM2.5), may be a neglected risk factor for diabetes. As a main component of haze, smoke, and motor vehicle exhaust, PM2.5 is dangerous in part because of its small size and ability to invade critical human organs in the respiratory and vascular systems. Exposure to higher levels of air pollution exaggerates adipose inflammation and insulin resistance in a mouse model of diet-induced obesity. In diabetic patients, plasma inflammatory markers increase in response to higher PM2.5 exposure.

Previous laboratory studies have found precursors to diabetes resulting from exposure to particulate air pollution, but this is among the first efforts to examine the connection on a large scale, examining actual human populations.

To do so the scientists examined EPA data on PM2.5 pollution from the entire contiguous US between 2004 and 2005 and checked it against Centers for Disease Control and US Census data on prevalence of adult diabetes and what other risk factors might be at play.

The result was a "strong and consistent association" between this type of air pollution and diabetes prevalence. For ever 10 µg/m3 increase in PM2.5 exposure, diabetes prevalence increased 1%. Even in places where pollution was within EPA limits, the highest areas had a 20% increase in diabetes prevalence over the lowest areas.

The one caveat in this, and an acknowledged area where further research is needed, according to study leader Dr John Brownstein: "We didn't have data on individual exposure, so we can't prove causality, and we can't know exactly the mechanism of these people's diabetes. But pollution came across as a significant predictor in all our models." (Science Daily)